Chrome: Animated GIFs are great, but they can get annoying on pages when they're constantly repeating the animation and you're trying to concentrate on the text. Paused! is a Chrome extension that stops animations after the first run and you can restart them with a click.

Paused! isn't exactly perfect. The animation doesn't stop until the page is completely loaded, and sometimes when you restart the animation you can't stop it again until you reload the page. Still, if an animated GIF in an article is annoying you it's a great way to keep them from constantly grabbing your attention.